Prime Guard ULTRAPURE DEF 2.5 Gal single-pack box includes a nozzle for an easy pour.Environmentally friendly solution for Selective Catalytic Reduction (SCR) systems. Meets the stringent ISO 22241, AUS 32 and DIN 70070 standards for purity and concentration. Formaldehyde-free, NOx reducing treatment specifically formulated for diesel engines equipped with SCR systems.API certified for proper SCR operation. Meets or exceeds all EPA standards.